It is known that extracorporeal contact of blood with synthetic materials activates the coagulation mechanism and coagulation occurs. Current research shows that cooling the blood in an external circulation lowers to a significant extent its undesirable coagulation, which means a big potential for medicine. Patients with kidney diseases are a numerous group which could benefit significantly from this discovery. This new principle of preventing the natural blood coagulation (Krou{hacek over (z)}eck{grave over (y)}, A. et al., Intensive Care Med (2009) 35:364-370, CZ300266, DE102008062424, U.S. 2010114003) could replace the current practice which uses other “anticoagulation” mechanisms (e.g. heparin), often with numerous undesirable effects. The basic prerequisite for the efficiency of this new principle is providing sufficient cooling and then heating (prior to entering the body circulation) of blood by means of a special heat exchanger. Both heat exchangers suitable for technical purposes and heat exchanger intended for medical use, namely for cooling/heating of blood, are known from the state of the art.
An exchanger serving as a heater or cooler of water, steam, oil etc., containing a bundle of tubes, was described in the patent CZI33689. Another tube heat exchanger, suitable for technical purposes, is disclosed for example in the patent CZ269522.
A heat exchanger suitable for blood is disclosed in U.S. Pat. No. 4,177,816, where the tubes for leading blood are of metal and contain inserts (for example in the shape of a strip) for ensuring the laminar flow of blood.
A tube heat exchanger made of plastics, suitable for medical use, i.e. for cooling/heating of blood, is disclosed in JP56059197. The exchanger disclosed in JP2102661 tries to achieve a higher efficiency of heat exchange by leading the cooling liquid through metallic tubes inside the body of the exchanger and blood flows through the body of the exchanger.
Another example of a heat exchanger for medical use is the exchanger disclosed in U.S. Pat. No. 5,294,397.
All the cited documents mention as a serious problem the homogeneity and efficiency of cooling/heating. None of the disclosed exchangers where blood flows in tubes places inside the housing containing the cooling/heating liquid contains any device or any construction element providing uniform laminar flow of the cooling/heating liquid, thus ensuring a high homogeneity and efficiency of blood cooling/heating. The efficiency of such a type of the exchanger is dependent, among others, on the quality of flowing of the cooling/heating liquid, which none of the prior art documents addressed. The flowing of the cooled/heated liquid, i.e. blood, does not pose any problem, since blood flows through thin tubes (capillaries) and basically it is always a laminar flow. On the other hand, the flowing of the cooling/heating liquid in the vessel of the exchanger (relatively high volume) by its character (turbulent, laminar) significantly influences the efficiency of the exchanger which is an important aspect not only in medical use.
In the medical practice, there is always a need of an efficient and relatively cheap (suitable for one use) device for blood cooling/heating. The inventors therefore designed a new heat exchanger containing a new element—laminarizer—which regulates the flow of the cooling/heating liquid so that the flow is uniform, which eliminates blind spots in the body of the exchanger and increases the cooling/heating effect of the heat exchanger.